Flexible fuel variable boost supercharged engine

ABSTRACT

The present invention provides a flexible fuel, spark ignition, variable boost, supercharged internal combustion engine. A variable speed drive assembly connects the engine output to a supercharger. The engine includes a fuel sensor which provides a signal to an engine controller which determines the type of fuel. The engine controller also receives signals from a mass air flow sensor, a manifold air pressure sensor, a crank angle sensor, a camshaft angle sensor, an oxygen sensor in the exhaust stream and a transmission controller. The engine controller provides control signals to an ignition module, to a fuel injection system, to an electronic throttle control, to a supercharger drive controller and to the transmission controller

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/956,528, filed on Aug. 17, 2007. The disclosure of the aboveapplication is incorporated herein by reference.

FIELD

The present disclosure relates to a flexible fuel, supercharged internalcombustion engine and more particularly to a flexible fuel, superchargedinternal combustion engine having variable boost.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may or may not constitute priorart.

Internal combustion engines, particularly those configurations utilizedin passenger car and light truck applications, have been the subject ofextensive and exhaustive development effort. One of the more recentresults of such effort involves the operation of an internal combustionengine as a flexible fuel engine, i.e., an engine operating on a varietyof fuels, most commonly gasoline and E85 (a mixture of 85 percentethanol (grain alcohol) and 15 percent gasoline). While a flexible fuelengine presently offers certain advantages from the standpoints of fuelexpense and the larger issue of foreign oil dependency, there areoperational issues which are the subject of significant contemporaryresearch and development.

For example, spark ignition internal combustion engines operating onethanol or E85 have better knock tolerance when operating under wideopen throttle or full load conditions than the same engine operating ongasoline. Because by its very nature the flexible fuel engine mustoperate on a variety of fuels, its operation on ethanol is very oftencompromised. Improving the performance and efficiency of a flexible fuelengine operating on ethanol is thus an important goal and the goal towhich this invention is directed.

SUMMARY

The present invention provides a flexible fuel, spark ignition, variableboost, supercharged internal combustion engine. A variable speed driveassembly connects the engine output to a supercharger. The variablespeed drive assembly may be either a continuously variable or a step,i.e., two speed, device. The intake manifold may also include asupercharger bypass which selectively connects the air duct upstream ofthe supercharger to the intake plenum downstream of the supercharger.

The engine includes a fuel sensor which provides a signal to a masterengine controller which determines the type of fuel. The master enginecontroller also receives signals from a mass air flow sensor, a manifoldair pressure sensor, a crankshaft angle sensor, a camshaft angle sensor,an oxygen sensor in the exhaust stream and a transmission controller.The master engine controller provides control signals to an ignitionmodule, a fuel injection system, an electronic throttle control, asupercharger drive controller and the transmission controller.

When the internal combustion engine is fueled with gasoline, theoperation of the supercharger will generally be somewhat limited. Infact, during low load and speed conditions, it may be desirable todisengage the supercharger to prevent any manifold pressure boost.

When the engine controller senses that the engine is fueled withethanol, E85 or another ethanol/gasoline blend, this information, inconjunction with other signals, is utilized to set a target boostpressure. The actual manifold pressure or a signal representing thespeed of the supercharger can be used as a feedback signal forsupercharger speed control. The maximum supercharger boost levels foreach fuel as a function of engine speed are stored in memory in theengine controller. If the desired engine torque is sufficiently high,the supercharger speed and boost are increased by adjustment of thevariable speed drive assembly to boost the volumetric efficiency of theengine to a level that better matches the fuel octane characteristics.

Thus it is an object of the present invention to provide a flexiblefuel, spark ignition, variable boost, supercharged internal combustionengine for use in motor vehicles.

Further objects, advantages and areas of applicability will becomeapparent from the description provided herein. It should be understoodthat the description and specific examples are intended for purposes ofillustration only and are not intended to limit the scope of the presentdisclosure.

DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a diagrammatic illustration of a first embodiment of aflexible fuel, supercharged, variable boost, internal combustion engineassembly according to the present invention; and

FIG. 2 is an enlarged, diagrammatic view of a portion of anotherembodiment of a flexible fuel, supercharged, variable boost, internalcombustion engine assembly according to the present invention.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses.

With reference to FIG. 1, a first embodiment of a flexible fuel, sparkignition, supercharged, variable boost, internal combustion engineassembly according to the present invention is illustrated and generallydesignated by the reference number 10. The flexible fuel internalcombustion engine assembly 10 includes an internal combustion engine 12typically having four, six or eight pistons and cylinders and acrankshaft or output shaft 14 which directly drives a multiple speed,typically automatic transmission 16 which, in turn, drives a final drivearrangement (not illustrated). Operatively associated with the internalcombustion engine 12 is an ignition system 18 which is controlled by amaster engine controller 20. The master engine controller 20 alsoprovides data to and controls a transmission controller 22, a fuelinjection system 24, an electronic throttle control 26 and asupercharger drive controller 28. The fuel injection system 24 may beeither port or direct (in cylinder) injection type.

The master engine controller 20 also receives a plurality of datasignals from: a camshaft angle sensor 32, an exhaust gas (oxygen) sensor34, a crankshaft angle sensor 36, a fuel sensor 38, a manifold airpressure (MAP) sensor 42 and a mass air flow (MAF) sensor 44. The massair flow sensor 44 is located in an air inlet duct 46 upstream of athrottle assembly 48. Downstream of the throttle assembly 48 is asupercharger 50 which is driven through a variable speed drive assembly52 from the crankshaft or output shaft 14 of the internal combustionengine 12 by suitable pulleys 54 and a belt 56 or other mechanicalconnection. Alternatively, energy may be supplied to the supercharger 50by an electric motor (not illustrated) or a combination of both theengine 12 and the electric motor.

The variable speed drive assembly 52 may be either a continuouslyvariable type or may provide stepped or two speed operation: directdrive and a fixed speed increase. Thus, it may include a CVT orplanetary gear type drive assembly which is controlled electrically orhydraulically. In any case, the typical maximum speed ratio increasewill be on the order of 1 to 2.5 to 1.0 to 4.0 although a lower minimum(speed increase) ratio or a higher maximum (speed increase) ratio may bedictated by certain applications. The inlet (suction) side of thesupercharger 50 is connected to the air inlet duct 46 and the outlet(pressure) side of the supercharger 50 is connected to an intakemanifold 58 in which the manifold air pressure sensor 42 resides.

Fuel in a fuel line 62 is provided to the fuel sensor 38 and thence tothe fuel injection system 24 and such fuel and air from the intakemanifold 58 is provided to the internal combustion engine 12. An exhaustmanifold 64 secured to the engine 12 contains the exhaust gas sensor 34and routes exhaust gasses to an exhaust system (not illustrated).

Referring now to FIG. 2, a partial view of another embodiment of aflexible fuel, spark ignition, supercharged, variable boost, internalcombustion engine assembly according to the present invention isillustrated and generally designated by the reference number 100. In theother embodiment of the flexible fuel, spark ignition, supercharged,variable boost, internal combustion engine assembly 100, a bypass duct102 extends from and communicates between the portion of the inlet airduct 46 downstream of the throttle assembly 48 and the intake manifold58. A two position or fully modulatable bypass valve 104 is controlledby the master engine controller 20 (illustrated in FIG. 1) and controlsthe quantity of air bypassing the supercharger 50. The bypass valve 104is especially useful to control air flow in conjunction with a two speedvariable speed drive assembly 52. A primary air duct 106 communicatesbetween the output of the supercharger 50 and the intake manifold 58.Finally, a supercharger speed sensor 108 may be utilized to provide dataor a signal to the master engine controller 20 regarding the speed ofthe shaft (not illustrated) of the supercharger 50. It should beunderstood that those components of the first embodiment of the flexiblefuel, spark ignition, supercharged, variable boost, internal combustionengine assembly 10 illustrated in FIG. 1 but not illustrated in FIG. 2are nonetheless components included and utilized in the other embodiment100 illustrated in FIG. 2 and that they function the same as thosecomponents illustrated in FIG. 1.

With reference now to FIGS. 1 and 2, the operation of a flexible fuel,spark ignition, supercharged, variable boost, internal combustion engineassemblies 10 and 100 according to the present invention will now bedescribed. Fuel is supplied in the fuel line 62 to the fuel sensor 38which provides data or a signal to the master engine controller 20 fromwhich it is determined what type of fuel or blend of fuels is currentlybeing provided to the internal combustion engine assembly 10.Alternatively, the master engine controller 20 may contain a softwarealgorithm which determines the type of fuel or blend based upon sensedengine and operating conditions. If it is determined that the fuel isgasoline, operation of the supercharger 50 will typically be limited to,at most, high load, high speed operation. The maximum boost pressure forgasoline as a function of engine speed is stored in memory in the masterengine controller 20. In many applications with gasoline, the bypassvalve 104 may be utilized and opened and operation of the supercharger50 may be disabled to avoid any manifold pressure boost.

If the fuel sensor 38 senses or provides data indicating the presenceand relative ratio of ethanol, the master engine controller 20, inconjunction with other data signals, sets a target boost pressure. Themanifold pressure sensed by the manifold air pressure sensor 42 or asignal from the supercharger speed sensor 108 may be utilized as afeedback signal to control the speed of the supercharger 50 and thus thepressure in the intake manifold 58. The maximum permissible boostpressures for each type or blend of fuel as a function of engine speedare stored in memory in the master engine controller 20.

When ethanol is present in the fuel and the desired torque of the engine12 is sufficiently high, the speed of the supercharger 50 will be raisedfrom those speeds associated with gasoline by controlling the variablespeed drive assembly 52 to increase the pressure of air delivered to theintake manifold 58 to boost the volumetric efficiency of the engine 12to a level that better matches the fuel octane characteristics. Manifoldpressure (boost) in the range of from 2.5 bar to 3.0 bar absolute aresuitable for fuels containing ethanol and many operating conditionsalthough it should be understood that this range is provided by way ofexample only and that various operating conditions and parameters aswell as diverse performance goals will typically widen this range.Additionally, the spark timing controlled by the ignition system 18 andthe duration of fuel injection pulses controlled by the fuel injectionsystem 24, both under the control of the master engine controller 20,are adjusted accordingly for the extra air flow and fuel type. Finally,the master engine controller 20 will typically generate commands to thetransmission controller 22 to adjust the shift point schedule of theautomatic transmission 16 and the lockup schedule of a torque converter(not illustrated) to optimize vehicle performance and fuel economy.

The foregoing description of the invention is merely exemplary in natureand variations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

1. A flexible fuel, supercharged internal combustion engine assemblycomprising, in combination, an internal combustion engine having anintake manifold and an output shaft, a supercharger having an inputshaft and an output provided to said intake manifold, a variable speeddrive assembly operably disposed between said output shaft and saidinput shaft, a plurality of sensors including at least a fuel sensor anda mass air flow sensor, a master engine controller having a plurality ofinputs for receiving data from said plurality of sensors and at leastone output for controlling said variable speed drive assembly.
 2. Theflexible fuel, supercharged internal combustion engine assembly of claim1 wherein said variable speed drive assembly includes an adjustablespeed increasing portion and a control portion for receiving said atleast one output of said master engine controller.
 3. The flexible fuel,supercharged internal combustion engine assembly of claim 1 wherein saidplurality of sensors further includes a manifold air pressure sensor andan oxygen sensor.
 4. The flexible fuel, supercharged internal combustionengine assembly of claim 1 wherein said plurality of sensors furtherincludes a crank angle sensor and a camshaft angle sensor.
 5. Theflexible fuel, supercharged internal combustion engine assembly of claim1 further including an automatic transmission and a transmissioncontroller linked to said master engine controller.
 6. The flexiblefuel, supercharged internal combustion engine assembly of claim 1further including a fuel injection system and an ignition system linkedto said master engine controller.
 7. The flexible fuel, superchargedinternal combustion engine assembly of claim 1 wherein said variablespeed drive assembly is one of a two speed or a continuously variabletype.
 8. A flexible fuel, spark ignition, supercharged internalcombustion engine assembly comprising, in combination, an internalcombustion engine having an intake manifold and an output shaft, asupercharger having an input shaft and an output provided to said intakemanifold, an adjustable drive assembly operably disposed between saidoutput shaft and said input shaft, a spark ignition system, a pluralityof sensors including at least a fuel sensor, a mass air flow sensor anda crankshaft angle sensor, a master engine controller having inputs forreceiving data from said plurality of sensors and outputs forcontrolling said adjustable drive assembly and said spark ignitionsystem.
 9. The flexible fuel, spark ignition, supercharged internalcombustion engine assembly of claim 8 wherein said adjustable driveassembly includes a speed increasing portion and a control portion forreceiving one of said outputs of said master engine controller.
 10. Theflexible fuel, spark ignition, supercharged internal combustion engineassembly of claim 8 wherein said plurality of sensors further includes amanifold air pressure sensor and an oxygen sensor.
 11. The flexiblefuel, spark ignition, supercharged internal combustion engine assemblyof claim 8 wherein said plurality of sensors further includes a camshaftangle sensor.
 12. The flexible fuel, supercharged internal combustionengine assembly of claim 8 further including an automatic transmissionand a transmission controller linked to said master engine controller.13. The flexible fuel, supercharged internal combustion engine assemblyof claim 8 further including a fuel injection system linked to saidmaster engine controller.
 14. The flexible fuel, supercharged internalcombustion engine assembly of claim 8 wherein said adjustable driveassembly is one of a two speed or a continuously variable type.
 15. Theflexible fuel, supercharged internal combustion engine assembly of claim8 further including an electronic throttle control and wherein saidmaster engine controller includes an output linked to said electronicthrottle control.
 16. A flexible fuel, supercharged internal combustionengine assembly comprising, in combination, an internal combustionengine having an intake manifold, a fuel injection system and an outputshaft, a supercharger having an input shaft and an output provided tosaid intake manifold, a variable speed drive assembly operably disposedbetween said output shaft and said input shaft, a plurality of sensorsincluding at least a fuel sensor and a mass air flow sensor, a masterengine controller having inputs for receiving data from said sensors andoutputs for controlling said variable speed drive assembly and said fuelinjection system.
 17. The flexible fuel, supercharged internalcombustion engine assembly of claim 16 wherein said variable speed driveassembly provides two selectable speed ratios.
 18. The flexible fuel,supercharged internal combustion engine assembly of claim 16 whereinsaid variable speed drive assembly includes a continuously variabletransmission.
 19. The flexible fuel, supercharged internal combustionengine assembly of claim 16 further including an automatic transmissionand a transmission controller linked to said master engine controller.20. The flexible fuel, supercharged internal combustion engine assemblyof claim 16 further including a manifold air pressure sensor, an oxygensensor and a crankshaft angle sensor.